It is known to continuously supply to a roll hub or core flat products of the most varied types and to roll or wind same onto said hub or core (cf. e.g. German patent 2 207 556, Swiss patent application 1 788/86-0). Particularly in printing technology, the printed products are preferably in stream formation and are supplied to the winding station in this way and are wound up to form rolls. If the number of products to be processed in this way is greater than the capacity of a roll, as soon as the latter is full, measures must be taken in order to be able to wind the continuously arriving products onto another empty roll hub. In the simplest, but uneconomic manner, it would e.g. be possible to interrupt the working process and during said interruption to replace the full roll by an empty roll hub.
In addition, Swiss patents 654 553 and 654 554 disclose a process and an apparatus making it possible in the case of only a single winding station with an additional intermediate roll to replace the main roll of the winding station without interrupting the working process. However, the products must be wound in double layer form and for further processing must be subdivided by a special means back into two separate scale or stream flows. If a roll is to be further processed in another working area, such additional means must be provided there for unwinding the double roll. As a function of the intermediate roll capacity and as a result of the double layer form of the wound products on the main roll, in this process it is necessary to replace the roll at relatively short intervals.
DE-OS 33 04 219 discloses an apparatus for stacking printed sheets. The printed sheets supplied by means of a feed conveyor are transferred to a conveyor belt of the apparatus. It is obvious that during this transfer the phase relationship of the printed sheets, i.e. the information concerning the reciprocal overlap or displacement of the printed products, is lost and the sheets are necessarily differently arranged due to the feed taking place at right angles to the conveyor belt. Thus, said apparatus can only be used if there is a subsequent intermediate stacking of the printed products and no significance is attached to the modified phase relationship during further processing. However, in many uses it is desirable or necessary to retain the phase relationship of the printed products throughout all the working stages and also during intermediate storage. Therefore, without additional complicated and expensive measures, said apparatus cannot be used for such purposes. In addition, with said apparatus it is not possible to freely select the reciprocal positioning of the printed sheets on the discharge conveyor. A further disadvantage is that it is not possible, or is only possible with considerable effort and expenditure, to replace the individual rolls or storage rolls because they are juxtaposed in parallel, access to the individual rolls is substantially impossible and consequently the apparatus can only be used to a limited extent as an off-line buffer store.
It is known from DE-OS 25 44 135 to provide two alternately loadable winding stations, in which articles are in each case supplied to one, while the full roll is removed from the other winding station. However, this solution in this form can only be used to a limited extent within an overall process, because the rolls must be supplied to another installation for further processing either manually, or at the best by using handling equipment, i.e. the apparatus constitutes a "dead-end" within a continuous process. Additional stations must be provided for unwinding purposes. Moreover, the right-angled path of the conveyor belts at the transfer locations leads to problems as in the case of DE-OS 33 04 219, because the relative arrangement of the products is necessarily and undesirably modified.
In many applications, e.g. in the printing field, the products for different processing operations occur in a specific arrangement. Thus, newspapers on conveyors are conveyed with the cording first whereas journals and magazines are conveyed with the head or bloom first. Obviously the reciprocal arrangement of the products can vary with regards to a number of other parameters (phase relationship, overshot/undershot conveying, spatial position, etc.). In order to be able to process products with different parameters in a following, standardized process or special machines, it is consequently necessary to convert or standardized these parameters associated with the products. Apparatuses are generally known which, by means of rewinding, convert printed products wound in undershot manner on to a roll and which in the case of mere unwinding would be obtained in overshot manner, into an undershot product flow again. The hitherto known apparatuses of this type have always been specifically intended for given uses and consequently only permit a limited conversion of such parameters. These apparatuses also provide no possibility for the buffer storage of products.